Vaisala WAA151 - Manual (Page 18)

User's Guide ________________________________________________________
16 _____________________________________________________ M210293en-A
Replacing Consumables
Replacement of the bearings should only be done by a
trained technician. To replace the ball bearings, follow the
procedure below and refer to Figure 6 on page 19.
1. Open the cup wheel fixing screw with a 2-mm Allen
key. Remove the cup wheel assembly.
CAUTION The cup wheel fixing screw has been treated with sealant.
Do not remove the fixing screw to ensure perfect sealing
after reassembling.
2. Loosen the hex nut of the connector (use a 22-mm
tool).
CAUTION Be careful not to bend the connector pins.
3. Loosen the three pan head screws at the bottom of the
sensor body (use a 7-mm tool).
4. Remove the lower body assembly by pulling it straight
outwards.
5. Loosen the spacer screws with a 7-mm tool and
disconnect the heating element outlet.
6. Remove the printed circuit board including the opto-
coupler.
CAUTION Do not twist or bend the connector. This may break the
pins.
7. Loosen the fixing screw of the chopper disc with a 2-
mm Allen key and remove the chopper disc.
8. Remove the external retaining ring (using narrow-
pointed pliers).
9. Remove the spacer ring.